1. Field of the Invention
The present invention relates to a wafer planarization apparatus, and more particularly to a wafer planarization apparatus for manufacture of a semiconductor wafer, where the reverse, on which no chip is formed, of a semiconductor wafer is ground, the ground wafer is adhered on a wafer frame for dicing through a sheet, and a protective sheet previously adhered on the surface of the wafer is peeled from the wafer.
2. Description of the Related Art
In recent years, thinner semiconductor elements are needed because of demand for IC cards. In the manufacture of the semiconductor elements, a predetermined circuit pattern (chips) is formed on the obverse of a semiconductor wafer, and the reverse of the semiconductor wafer is then ground by a planarization apparatus or a back grinder so that the semiconductor wafer is thinned. Since the planarization apparatus grinds the reverse of the wafer while holding the obverse of the wafer, on which the chips are formed, with a holding part, it is necessary to protect the chips from the holding part, and a chip protective sheet is adhered to the obverse of the wafer before the grinding process.
The wafer of which reverse has been ground by the planarization apparatus is taken out of the planarization apparatus and transported to an inspecting stage, and the wafer is inspected visually for the thickness, cracks and so forth. The wafer that is determined as of sufficient quality in the inspecting stage is moved to a wafer frame adhering stage or a frame mounter, and a wafer frame is adhered to the wafer through a sheet. Then, the protective sheet is peeled from the wafer. Thereafter, the wafer is set to a cutting part of a dicing machine with the wafer frame, and is divided into chips by a blade of the dicing machine.
As described above, conventionally, the planarization apparatus, the inspecting stage and the frame mounter are separately provided, and the operator transfers the wafers processed in one of the apparatuses to another so that a series of processes (grinding, inspection, adhesion of the wafer frame, and peeling of the protective sheet) is carried out.
Recently, it is proposed to provide a robot for transporting the wafer ground in the planarization apparatus to the frame mounter so that the processes of grinding of the wafer, adhesion of the wafer frame, and peeling of the protective sheet are systematized in line. However, the wafer planarization apparatus to be conventionally systematized in line is not provided with the inspecting stage, so that there is a problem that even the imperfect wafer that should be rejected is transported to the frame mounter and is adhered to the wafer frame.
For example, the wafer with the thickness over the predetermined thickness should be returned to the planarization apparatus so as to be processed again. In the wafer planarization apparatus with no inspecting stage, however, even the overthick wafer is adhered to the wafer frame. It is difficult to process again the wafer adhered to the wafer frame, and the yield of wafers thus deteriorates.